Unless you're using Java SE 6, you will also need the JavaBeans Activation Framework (JAF) extension that provides the javax.activation package.suggestion is to use version 1.1.1 of JAF, the latest release. JAF is included with Java SE 6

You just need to download it separately. And like Neha said, you have to downloade JAF as well if you're JDK / JRE is older than 1.6

By the way, Neha Java? Your name sounds a lot like a nickname, with neha meaning love in Hindi. Now it's also used as a girl's first name, but combined with your last name (Java) it's highly suspicious.